KR20100003255A - Communication apparatus for vehicles using visible light communication and method thereof, and intelligent transport system using the same - Google Patents

Abstract

PURPOSE: A communication apparatus for vehicles by visible light communication and a method thereof, and an intelligent transport system using the same are provided to continue communication between vehicles using street lights even when a communication failure occurs. CONSTITUTION: A visible light transmitter(210) transmits data through visible light communications to outside. A visible light receiver(220) receives data through the visible light communications from outside. A communication processor(230) controls a vehicle to communicate with other vehicles through street lights capable of visible light communications.

Description

Vehicle-to-vehicle communication device using visible light communication and its communication method, and intelligent transportation system using the same {COMMUNICATION APPARATUS FOR VEHICLES USING VISIBLE LIGHT COMMUNICATION AND METHOD THEREOF, AND INTELLIGENT TRANSPORT SYSTEM USING THE SAME}

The present invention relates to an inter-vehicle communication device using visible light communication, and in particular, an inter-vehicle communication device capable of continuously performing communication between vehicles by using street lamps around the vehicle when communication between vehicles is impossible due to the distance between vehicles and the surrounding environment. The present invention relates to a communication method and an intelligent transportation system using the same.

Intelligent transportation systems combine software technologies, such as communications, electronics, control, and computing technologies, with hardware-centric infrastructure, such as roads and vehicles, to enable vehicles and infrastructure to complement each other to ensure safe, comfortable, and efficient traffic. It is an integrated system between a traffic network and an information communication network that makes it feasible.

Looking at the major changes in the global telematics market, the concept of telematics is changing from a safety-oriented service to a location based service (LBS) based service using location information. It is becoming. Since the business model of the call center-oriented operator interface such as GM OnStar is difficult to expect sufficient profit generation, it is recently changing to the machine interface of the terminal itself using voice recognition.

The telematics communication infrastructure currently utilizes the second generation cellular network, but the next generation of cellular mobile communication technology (HPi (high-speed portable internet), fourth generation mobile communication and dedicated short range communications (DSRC) communication, and wireless local area (WLAN) It is expected that the telematics communication network will be advanced by utilizing network (WBro) communication, WiBro (Wireless Broadband) communication, and DMB (Digital Multimedia Broadcasting) technology to provide high-speed multimedia services in the vehicle. ISO TC204 standardizes the Communication Air Interface Long and Medium Range (CALM) standard that accommodates cellular, DSRC, and IR (Infra-Red) methods to organically combine features to support high-speed mobility and omnidirectional networking of vehicles. It is also on the ground to support mass multimedia services such as movies and games. Standardization of interworking protocols with uplinks for satellite and satellite DMB technology is also being driven by 3GPP (3G Partnership Project), and is focused on IEEE 802.11 to add security, authentication, handover, and high-speed data transmission to WLAN. Standardization is in progress.

The existing research on the field of communication of domestic and foreign intelligent transportation system is based on radio frequency (RF). With various services using these radio frequencies, the wireless communication area is gradually reaching a saturation state, and development and installation of various terminals are required to provide a communication system based on the radio frequency. Accordingly, there is a need for a communication means that can replace the existing communication method, a wireless communication method, and an intelligent transportation system using such communication means is also required.

In this regard, infrared communication, a wireless optical communication system that has been proposed and studied as an alternative, provides ultra-wide bandwidth but due to the disadvantages of infrared light, the transmission power is controlled according to the Eye-safety standard set by the International Organization for Standardization (ISO). Limited

Accordingly, in order to increase reception rate, both transceivers use a device having a narrow field of view (FOV). As a result, when the FOV between the transmitter / receiver ends or the physical obstacle exists, the communication is disconnected.

In order to improve this, visible light communication technology, a communication technology for transmitting information using visible light, which is visible light of a human eye, has been proposed. The visible light communication technology mainly transmits data by modulating or blinking a frequency using visible light emitted by a device equipped with an LED such as a lighting device or a display device.

However, when a vehicle performs only a vehicle-to-vehicle communication using a visible light communication device adopting such a visible light communication technology on a road, communication between vehicles is smoothly performed due to a failure in communication performed by a distance change between vehicles or the surrounding environment. It may not be performed.

On the other hand, researches are being actively conducted to convert and develop wireless ad hoc networking technology into more popular and commercial civilian services such as providing wireless Internet service as well as military or special purpose. A new technology emerging naturally in this process is the "wireless mesh network" technology.

1 is a conceptual diagram for a general wireless mesh network.

Wireless mesh network technology is equipped with networking functions such as multi-hop routing to access points used in existing wireless LANs and connected to each other using wireless communication technology to cover a wide area without connecting to a wired network. It is a skill. Currently commercialized wireless LAN service such as KT Netspot has the advantage of enabling high speed data communication of 2Mbps or more, while network access is possible only in a specific area (hot-spot) where AP is installed, so network expansion is not easy and There is a drawback to installing a large number of APs to cover the same wide area.

But with wireless mesh networking technology, every AP does not need to be connected to a wired network, making it possible to offer wireless Internet services in a wider area at lower installation costs.

In reality, the US, where the concept of a wireless mesh network was first introduced, is unlikely to build a nationwide high-speed Internet network such as ADSL. Not only is the region wide, but there are many regions with very low population densities. However, if wireless mesh routers (MRs) are installed in various places using wireless mesh network technology, high-speed internet service can be provided at a lower cost.

Philadelphia and San Francisco are attempting to build a wireless mesh network that covers the entire city as part of public projects to provide low-cost Internet services to low-income households. The public wireless mesh LAN project is nearing completion.

The same is true for the domestic situation, but the domestic communication environment is almost the world's highest level in comparison with the world, but only in the city center of the country, that is, the densely populated area. It is true that high speed internet service is meaningless even a little out of the downtown area.

Local governments in Korea are currently building and operating their own communication networks and services (eg BIS, traffic management, etc.) by leasing communication lines from ISPs such as KT. As a result, a huge amount of network usage fees are being spent every year, and some local governments are promoting their own network construction as an alternative to this, and the wireless mesh network is being actively reviewed.

Wireless mesh network technology is a ubiquitous network-oriented total solution, not just the concept of data services such as high-speed Internet service. In other words, the data service is possible, and this structure is used for the Wi-Fi network, the cellular network, the WiMAX network, the sensor network, the wireless client and the wired client. It can be linked with various kinds of networks such as networks.

Therefore, it is highly likely to occupy a very important position in the future design of the communication network structure, and the range of application is very diverse with simple data service, public safety, sensor network, home network, etc., and has a huge ripple effect on society.

Accordingly, there is a need to provide a more efficient intelligent transportation system by integrating an inter-vehicle communication device that performs inter-vehicle communication using a visible light communication device and the wireless mesh network.

The technical problem to be achieved by the present invention is to perform the inter-vehicle communication using visible light communication, and the inter-vehicle vehicle through the visible light communication with the roadside mesh network formed by the street light when the road-to-vehicle communication becomes impossible due to obstacles, etc. An inter-vehicle communication apparatus and method for continuously performing communication, and an intelligent transportation system using the same are provided.

An inter-vehicle communication device according to one aspect of the present invention for achieving the technical problem is

An inter-vehicle communication device mounted in a vehicle and transmitting and receiving data through visible light communication with another vehicle, the apparatus comprising: a visible light transmitting unit transmitting data to the outside through visible light communication; Visible light receiving unit for receiving data from the outside through the visible light communication; And receiving information data to be transmitted to the outside from an upper processing unit in a vehicle, transmitting data to the other vehicle through the visible light transmitting unit, and transmitting data received from the other vehicle through the visible light receiving unit to the upper processing unit. When the visible light communication through the visible light transmitting unit and the visible light receiving unit is disabled due to a failure, the communication processing unit for controlling to communicate with the other vehicle through the street light around the vehicle capable of visible light communication.

In-vehicle communication method according to another aspect of the present invention,

An inter-vehicle communication method in which an on-vehicle communication device mounted in a vehicle transmits and receives data through visible light communication with another vehicle, the method comprising: performing visible light communication with another vehicle; Determining whether visible light communication with the other vehicle is stopped; And when the visible light communication is stopped, performing communication with the other vehicle through a street lamp around the vehicle.

Intelligent transportation system according to another feature of the present invention,

A plurality of vehicles each equipped with an inter-vehicle communication device configured to transmit and receive data through visible light communication; And a roadside mesh network in which a plurality of streetlights capable of visible light communication, wireless communication, or optical communication with each other form a mesh network node, and when the visible light communication between the plurality of vehicles becomes impossible, the mesh network of the roadside mesh network is impossible. It is characterized in that the communication continues between the plurality of vehicles through a street lamp as a node.

According to the present invention, continuous inter-vehicle communication can be performed even when a failure occurs in inter-vehicle communication by using a street lamp installed on the roadside.

In addition, by checking the environment in which vehicle-to-vehicle communication is possible and the environment in which it is impossible through visible light communication, it is possible to correspond to the radio frequency possessed by optical communication by applying the communication method organically between vehicle-to-vehicle, vehicle-to-streetlight, and streetlight-to-streetlight communication. Economic advantages of non-regulatory, non-regulation, the ability to send large amounts of data at high speeds compared to wireless communications, excellent security, and no band interference with radio frequencies If the vehicle-to-vehicle cannot be secured due to rain or fog, vehicle-to-vehicle communication is impossible.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Now, a vehicle-to-vehicle communication device using visible light communication according to an embodiment of the present invention will be described in detail.

2 is a diagram schematically illustrating a concept in which a vehicle equipped with an inter-vehicle communication device according to an embodiment of the present invention performs inter-vehicle communication.

As shown in FIG. 2, the inter-vehicle communication devices 11, 21, 31 are mounted on the vehicles 10, 20, and 30, respectively.

The inter-vehicle communication devices 11, 21, and 31 mounted on the vehicles 10, 20, and 30 may perform visible light communication to transmit and receive data to and from each other. Referring to the example shown in FIG. 2, the inter-vehicle communication device 11 of the vehicle 10 performs visible light communication with the inter-vehicle communication device 21 of the vehicle 20, and also communicates between the vehicles of the vehicle 20. The device 21 may perform visible light communication with the inter-vehicle communication device 31 of the vehicle 30. Therefore, the inter-vehicle communication device 11 of the vehicle 10 can communicate with the inter-vehicle communication device 31 mounted on the vehicle 30 through the inter-vehicle communication device 21 mounted on the vehicle 20. .

Since the vehicle-to-vehicle communication devices 11, 21, and 31 perform communication using visible light, the vehicle 10, 20, and 30 may perform visible light communication at the same time by using lighting such as headlights or taillights of the vehicles 10, 20, and 30. have.

Communication that performs optical communication using visible light communication and wireless communication or FTTH (Fiber to the home) even in the street lights 40, 50, 60, 70, and 80 installed on the side of the road on which the vehicle 10, 20, 30 runs. The devices 41, 51, 61, 71, 81 are mounted.

The street lights 40, 50, 60, 70, and 80 may transmit and receive data by performing visible light communication, wireless communication, or optical communication with each other using the communication devices 41, 51, 61, 71, and 81 mounted therein. have.

While the vehicles 20 and 30 are performing visible light communication with each other using the inter-vehicle communication devices 21 and 31 on the road, as shown in FIG. 2, the distance between the vehicle 20 and the vehicle 30 is When a situation occurs in which the visible light communication using the inter-vehicle communication devices 21 and 31 is not possible, the inter-vehicle communication devices 21 and 31 according to the embodiment of the present invention become disabled due to a failure in the performed visible light communication. And detecting visible light communication with the street lamps 40, 50, 60, 70, and 80 installed in the vicinity.

For example, since the street light 50 is provided in the vicinity of the vehicle 20, and the communication device 51 capable of visible light communication is mounted on the street light 50, the vehicle 20 is connected to the street light 50. Visible light communication with the communication device 51 is performed. Similarly, the vehicle 30 also performs visible light communication with the communication device 71 of the street light (for example, 70) installed in the vicinity. In this case, the street lights 50 and 70 may perform visible light communication, wireless communication, or optical communication using the street light 60 directly or by using the street light 60.

As described above, in the embodiment of the present invention, when a situation in which visible light communication between the vehicles 20 and 30 becomes impossible occurs, the inter-vehicle communication apparatuses 21 and 31 mounted on the vehicles 20 and 30 may be street lamps installed around the vehicle. By performing visible light communication with the communication devices 51 and 71 of the 50 and 70, as a result, the vehicles 20 and 30 can continue to communicate with each other through the street lights 50 and 70.

Hereinafter, the vehicle-to-vehicle communication devices 11, 21, and 31 according to an embodiment of the present invention will be described. Since the inter-vehicle communication devices 11, 21, 31 are identical to each other, the following description will be given with reference to the inter-vehicle communication device 21.

3 is a block diagram of an inter-vehicle communication device 21 according to an embodiment of the present invention.

As shown in FIG. 3, the inter-vehicle communication device 21 according to an exemplary embodiment of the present invention includes a visible light transmitter 210, a visible light receiver 220, and a communication processor 230.

The visible light transmitter 210 transmits the information data transmitted from the communication processor 230 to the outside through the visible light.

The visible light receiver 220 receives data transmitted from the outside through the visible light, demodulates the received data into corresponding received data, and transmits the demodulated data to the communication processor 230.

The communication processor 230 receives information data to be transmitted to the outside from the upper processing unit in the vehicle 20 and transmits it to the visible light transmitting unit 210, and receives and transmits the received data transmitted from the visible light receiving unit 220 to the upper processing unit. .

The communication processor 230 determines the communication state with the outside based on the data transmission / reception processing result of the visible light transmitter 210 and the visible light receiver 220, and if a failure occurs during the visible light communication with the external vehicle, the communication is no longer performed. Detect if it can't be done. In this case, the communication processor 230 searches whether there is an external street light through which the visible light can be communicated through the visible light transmitter 210 and the visible light receiver 220, and then, for example, the external street lights 40, 50, 60, 70. If there is a street light capable of visible light communication, such as the communication devices 41, 51, 61, 71, 81 of FIG. 80, the visible light communication is performed with the communication device of the corresponding street light.

Similarly, the inter-vehicle communication device 31 of another vehicle 30 that is performing visible light communication with the inter-vehicle communication device 21 of the vehicle 20 also has visible light communication with the inter-vehicle communication device 21 of the vehicle 20. Since it becomes impossible during this communication, visible light communication with another external street light is performed, and as a result, visible light communication that has been performed between the vehicles 20 and 30 through the street lights 40, 50, 60, 70, and 80 may continue. Can be.

In the embodiment of the present invention, the visible light transmitter 210 and the visible light receiver 220 may correspond to the headlamp or the taillight of the vehicle 20.

FIG. 4 is a diagram illustrating an example of the visible light transmitter 210 illustrated in FIG. 3.

As shown in FIG. 4, the visible light transmitter 210 includes a modulator 211, a multiplexer 210, a signal selector 213, and a visible LED unit 214.

The modulator 211 modulates a plurality of user-specific information data into signals of respective modulation schemes according to various modulation schemes, and modulates the signals on a carrier frequency that is a specific frequency band. The modulator 211 may include, for example, OOK (On Off Keying), PWM (Pulse Width Modulation), PPM (Pulse Position Mudulation), PAM (Pulse Amplitude Modulation), ASK (Amplitude Shift Keying), M-PSK ( Modulation is performed according to any one of modulation methods such as M-ary Phase Shift Keying (M-ary Phase Shift Keying) and M-ary Quadrature Amplitude Modulation (M-QAM).

As described above, the plurality of user-specific information data are modulated into a plurality of user-specific signals through the modulator 211 and output.

The multiplexer 212 multiplexes and outputs a plurality of user-specific signals output from the modulator 211.

On the other hand, since the visible light transmitting unit 210 according to the embodiment of the present invention corresponds to the lighting in the vehicle 20, it should basically perform a lighting function. That is, when it is necessary to perform the illumination function, the visible light transmitter 210 outputs the illumination light to the outside according to the illumination signal from the outside.

Therefore, the signal selector 213 selects and outputs any one of an illumination signal for performing an illumination function and a plurality of user-specific signals for performing a visible light communication function. That is, the signal selector 213 controls to output one of an illumination signal input from the outside and a plurality of user-specific signals multiplexed and output by the multiplexer 212. In addition, a control signal for controlling the signal selector 213 is output from the multiplexer 212 to the signal selector 213 as a communicable signal, and this communicable signal is a signal multiplexed by the multiplexer 212. It is output as a turn-on signal during the existing period. Therefore, the signal selector 213 is when the visible light communication apparatus according to the embodiment of the present invention performs the visible light communication function when the communication enable signal output from the multiplexer 212 is turned on. Select to output multiple user-specific signals multiplexed and output. However, when the communicable signal is turned off, since the visible light transmitter 210 performs an illumination function, the signal selector 213 selects and outputs an illumination signal input from the outside.

The visible light LED unit 214 includes one or more LEDs (hereinafter, referred to as "visible light LEDs") for converting an electric signal into an optical signal, in particular, an optical signal in the visible light region, and transmitting the signal, and outputting the signal from the signal selector 213. It transmits to the outside as visible light corresponding to. Therefore, when an illumination signal for performing an illumination function is selected and output from the signal selection unit 213, the visible light LED unit 214 operates only as an illumination lamp, but performs a visible light communication function in the signal selection unit 213. When a plurality of user-specific signals are selected and output, the visible light LED unit 214 operates as a lamp for performing visible light communication.

The visible light LED unit 214 may be made of any one of white-LED, red-LED, green-LED, blue-LED, yellow-LED, or multi-chip visible light LEDs (red, green, blue). LEDs using chips), single-chip visible LEDs (LEDs using red, green, blue, and yellow chips), and the like. Among these, White-LED which can be used as a lamp is mainly used as the visible light LED according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of the visible light receiver 220 illustrated in FIG. 3.

As shown in FIG. 5, the visible light receiver 220 includes a photo-detector 221, a receiver filter 222, an equalizer 223, a demultiplexer 224, and a demodulator 225. Include. Here, the visible light receiver 220 is used only when performing the visible light communication function, and is not used when performing the lighting function.

The photo detector 221 receives an optical signal transmitted from the outside, converts the optical signal into an electrical signal and outputs the converted electrical signal. The photodetector 221 is one of the semiconductor diodes and is configured of a photoelectric conversion element such as a photodiode mainly used for detecting an optical signal by generating a current corresponding to the received optical signal.

The reception filter unit 222 removes all carrier components for a specific frequency band component with respect to the electrical signal output from the photodetector 221 and performs a correlation process using a reference code to output the corresponding signal.

The equalizer 223 corrects and outputs a signal output from the reception filter unit 222. The equalizer 223 is already used in various wireless communication systems, and its functions and operations are the same or similar, and thus detailed description thereof will be omitted.

The demultiplexer 224 demultiplexes and outputs a signal output from the equalizer 223. At this time, the demultiplexing number corresponds to the number of users. That is, the demultiplexer 224 copies and outputs the signal output from the equalizer 223 to correspond to the number of users.

The demodulator 225 demodulates a plurality of user signals which are demultiplexed by the demultiplexer 224 and outputs the plurality of user signals according to various demodulation methods. Here, since the demodulation method performed by the demodulator 225 adopts the same method as the modulation method performed by the modulator 211 of the visible light transmitter 210, the demodulator 225 is, for example, OOK, PWM, PPM Modulation is performed according to any one of demodulation schemes such as PAM, ASK, M-PSK, and M-QAM.

6 is a detailed block diagram of the communication processor 230 shown in FIG. 3.

As shown in FIG. 6, the communication processor 230 includes a transmission and reception processor 231, a failure determination unit 232, a search unit 233, and a communication control unit 234.

The transmission / reception processor 231 performs visible light communication between the upper processing unit of the vehicle 20 and the outside through the visible light transmitter 210 and the visible light receiver 220.

The failure determining unit 232 determines whether the visible light communication is interrupted due to a failure while performing visible light communication with the outside based on the communication data through the transmission / reception processing unit 231.

When the visible light communication with the outside is interrupted due to a failure by the failure determining unit 232, the search unit 233 may display the vehicle in the street lamps 40, 50, 60, 70, and 80 outside the vehicle 20. Search whether there is a street light capable of visible light communication with the inter-vehicle communication device 20 in (20). For example, the searcher 233 searches for visible light communication with the communication device 51 of the street light 50 around the vehicle 20.

The communication control unit 234 controls the transmission / reception processing unit 231, the failure determination unit 232, and the search unit 233 to control visible light communication with the outside of the inter-vehicle communication device 21, and the failure determination unit 232. When it is determined that visible light communication with the outside is stopped and the communication device 51 of the street light capable of visible light communication is searched by the search unit 233, the visible light communication is performed with the communication device 51 of the found street light.

As such, even when visible light communication between the inter-vehicle communication device 21 of the vehicle 20 and the inter-vehicle communication device 31 of the external vehicle 30 is interrupted, the communication unit 230 of the external street light 50 The communication device 51 may be searched and interrupted visible light communication may continue to be performed.

Hereinafter, a method of performing inter-vehicle communication using visible light communication according to an exemplary embodiment of the present invention will be described with reference to FIG. 7.

In the embodiment of the present invention, as shown in FIG. 2, the vehicle 20 performs visible light communication with the inter-vehicle communication device 31 of the vehicle 30 through the inter-vehicle communication device 21, and the vehicle 20 It will be described on the assumption that the street light 50 is positioned around the vehicle 50 and the street light 70 is positioned around the vehicle 30.

First, the inter-vehicle communication device 21 of the vehicle 20 communicates with the inter-vehicle communication device 31 of the vehicle 30 by using the communication processor 230, the visible light transmitter 210, and the visible light receiver 220. Perform (S100).

As such, while the vehicle 20 is performing visible light communication with the vehicle 30, whether the visible light communication, which is performed by an external obstacle or an increase in distance between the vehicles 20 and 30, is interrupted is determined by the communication processor 230. The failure determination unit 232 determines (S110).

If it is determined by the failure determination unit 232 that the visible light communication is interrupted due to an external obstacle or an increase in the distance between the vehicles 20 and 30, the search unit 233 determines the street light around the vehicle 20. Search for a street light capable of visible light communication among the (40, 50, 60, 70, 80) (S120).

In this example, when the street light around the visible light communication, such as street light 50 is found (S130), the communication control unit 234 communicates the street light 50 found through the visible light transmitter 210 and the visible light receiver 220 Visible light communication with the device 51 is performed (S140).

The communication control unit 234 continues to communicate with the vehicle 30 through visible light communication with the street lamp 50 (S150). That is, the inter-vehicle communication device 31 of the vehicle 30 also performs visible light communication with the communication device 71 of the street light 70 after searching for the street light 70 due to the interruption of the visible light communication with the vehicle 20. Therefore, the inter-vehicle communication device 21 of the vehicle 20 and the inter-vehicle communication device 31 of the vehicle 30 are not directly visible light communication due to the mutual communication between the street light 50 and the street light 70. Communication via the street lights 50, 60, 70 can be continued.

Hereinafter, an intelligent transportation system using an inter-vehicle communication apparatus according to an embodiment of the present invention will be described.

8 is a view schematically showing an intelligent transportation system according to an embodiment of the present invention.

As shown in FIG. 8, an intelligent transportation system according to an exemplary embodiment of the present invention includes a vehicle 10, 20, 30 equipped with an inter-vehicle communication device 11, 21, 31 capable of transmitting and receiving data to each other through visible light communication. ) And a roadside mesh network 300 including a plurality of streetlights including a visible light communication, an external communication, or a communication device capable of optical communication, is formed as mesh network nodes.

Street lamps, which are mesh network nodes forming the roadside mesh network 300, may perform visible light communication, wireless communication, or optical communication with each other to transmit and receive data with each other. Referring to FIG. 2, among street lamps included in the roadside mesh network 300, streetlights 40, 50, 60, 70, and 80 are street lamps 40, 50, 60, 70, and 80. Form some of the mesh network nodes of 300. The street lights 40, 50, 60, 70, and 80 perform visible light communication, wireless communication or optical communication with each other through the communication devices 41, 51, 61, 71, 81 as described above to form a mesh network node. Send and receive data. In addition, the street lights 40, 50, 60, 70, and 80 in the roadside mesh network 300 may configure a communication network using multi-hops. That is, the street lamps 40, 50, 60, 70, and 80 may communicate with each other using a multi-hop.

The vehicle 10, 20, 30 performs visible light communication with each other through the inter-vehicle communication devices 11, 21, and 31, and performs visible light communication with the roadside mesh network 300 when the visible light communication between the vehicles becomes impossible. By performing the roadside mesh network 300 can be continued communication between the vehicle (10, 20, 30).

To this end, the inter-vehicle communication apparatuses 11, 21, and 31 mounted on the vehicles 10, 20, and 30 have roadside meshes when the visible light communication between the vehicles 10, 20, and 30 is interrupted as described above. Searching for street lamps belonging to the network 300 continues to perform visible light communication.

9 is a diagram schematically showing a method of performing communication between vehicles through an intelligent transportation system according to an embodiment of the present invention.

As illustrated in FIG. 9, the vehicles 400, 410, and 420 are each performing visible light communication through the inter-vehicle communication devices 401, 411, and 421 mounted therein, respectively. Due to the four-distance signal and the driving direction of the vehicle, the direct visible light communication, which is performed by the distance between the vehicles 400, 410, and 420, becomes impossible. Here, the inter-vehicle communication devices 401, 411, and 421 have the same functions as the inter-vehicle communication devices 11, 21, and 31 described above with reference to FIGS. 2 to 7.

On the other hand, a plurality of street lights are installed on the roadside of the road 600, and the plurality of street lamps are capable of transmitting and receiving data by performing visible light communication, wireless communication, or optical communication with each other as mesh network nodes of the roadside mesh network 300. It works. For example, the street lights 500, 510 and 520 are equipped with communication devices 501, 511 and 521 capable of visible light communication, wireless communication or optical communication, respectively. The communication apparatuses 41, 51, 61, 71, 81 described with reference to Figs. 2 to 7 and the functions thereof are all the same.

Therefore, the vehicle 400 searches the communication device 501 of the street light 500 which is a mesh network node belonging to the roadside mesh network 300 through the inter-vehicle communication device 401, and performs visible light communication with each other. The vehicle 420 searches for the communication device 511 of the street light 510 which is a mesh network node belonging to the roadside mesh network 300 through the inter-vehicle communication device 411, and performs visible light communication with each other. Searches for the communication device 521 of the street light 520 that is a mesh network node belonging to the roadside mesh network 300 through the inter-vehicle communication device 421 to perform visible light communication with each other.

As such, the street lights 500, 510, and 520 retrieved by the vehicles 400, 410, and 420 are mesh network nodes forming the roadside mesh network 300, and thus, may communicate with each other. The inter-vehicle communication devices 401, 411, and 421 of FIG. 420 can communicate with each other through the communication devices 501, 511, and 521 of the street lights 500, 510, and 520 forming the roadside mesh network 300. That is, even if visible light communication performed between the vehicles 400, 410, and 420 is interrupted due to the distance between the vehicles 400, 410, and 420, the suspended communication may be resumed through the roadside mesh network 300 formed nearby. It becomes possible.

Therefore, the vehicle 400, 410, 420 according to the embodiment of the present invention performs visible light communication between vehicles, and if the visible light communication between vehicles is impossible, the roadside mesh network formed of street lights 500, 510, 520 ( It is characterized in that to continue the communication between the vehicle through 300.

FIG. 10 is a diagram illustrating an example of an automatic network configuration when a failure occurs in a roadside mesh network in an intelligent transportation system according to an embodiment of the present invention.

As shown in FIG. 9, the vehicle 400, 410, and 420 may not be directly visible through the inter-vehicle communication devices 401, 411, and 421, and thus the vehicle 400 may be formed using the roadside mesh network 300 formed around the vehicle. , 410, 420 between the vehicle 400, 410, 420 by automatically forming a new path in the roadside mesh network 300 in the event of a failure in the roadside mesh network 300 during communication The communication can be continued.

Referring to FIG. 10, while the vehicle 400 continues to communicate using the streetlights 500 and 520, which are mesh network nodes of the roadside mesh network 300, the direct visible light communication with the vehicle 420 may not be possible. When a communication failure occurs between the street lamp 700 and the street lamp 700 around the street, the communication between the street lamps 520 and 700 becomes impossible, the street lamp 710 which is a new mesh network node of the roadside mesh network 300 becomes the street lamp 520. Instead, by automatically reconfiguring the network to form a new path, the vehicle 420 can continue to communicate with the vehicle 400 through the street light 710.

Meanwhile, in the above case, when direct visible light communication between the vehicles 400, 410, and 420 becomes impossible, the vehicles 400, 410, and 420 continue to communicate using the street lights 500, 510, and 520 of the roadside mesh network 300. Although only a description has been made of the present invention, the technical scope of the present invention is not limited thereto, and the vehicles 400, 410, and 420 continue to travel on the road 600 so that their positions are continuously changed. There is a case where continuous visible light communication with the street lamps 500, 510, and 520 in the vicinity of 420 becomes impossible. In this case, the inter-vehicle communication devices 401, 411, and 421 mounted on the vehicles 400, 410, and 420 search for a new street lamp that forms the roadside mesh network 300 again, and then the roadside mesh network 300 again. By forming a new path using the to maintain the communication between the vehicle (400, 410, 420).

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a conceptual diagram for a general wireless mesh network.

2 is a diagram schematically illustrating a concept in which a vehicle equipped with an inter-vehicle communication device according to an embodiment of the present invention performs inter-vehicle communication.

3 is a block diagram of an inter-vehicle communication device according to an embodiment of the present invention.

4 is a diagram illustrating an example of the visible light transmitter illustrated in FIG. 3.

FIG. 5 is a diagram illustrating an example of the visible light receiver illustrated in FIG. 3.

6 is a detailed block diagram of the communication processing unit shown in FIG. 3.

7 is a flowchart of a method for performing inter-vehicle communication using visible light communication according to an embodiment of the present invention with reference.

8 is a view schematically showing an intelligent transportation system according to an embodiment of the present invention.

9 is a diagram schematically showing a method of performing communication between vehicles through an intelligent transportation system according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating an example of an automatic network configuration when a failure occurs in a roadside mesh network in an intelligent transportation system according to an embodiment of the present invention.

Claims (13)

An inter-vehicle communication device mounted on a vehicle and transmitting / receiving data through visible light communication with another vehicle, A visible light transmitter for transmitting data to the outside through visible light communication; Visible light receiving unit for receiving data from the outside through the visible light communication; And Receives the information data to be transmitted to the outside from the upper processing unit in the vehicle and transmits the data to the other vehicle through the visible light transmitting unit, and transmits the data received from the other vehicle through the visible light receiving unit to the upper processing unit, the visible light When the visible light communication performed through the transmitter and the visible light receiver becomes impossible due to a failure, the communication processor controls to perform communication with the other vehicle through a street lamp around the vehicle capable of visible light communication. Inter-vehicle communication device comprising a. The method of claim 1, The visible light transmitting unit, A modulator which modulates data from the communication processor into a user-specific signal on a carrier frequency of a specific frequency band; A multiplexer for multiplexing and outputting the plurality of user signals modulated by the modulator; A signal selector configured to select and output one of an illumination signal input from the outside and a plurality of user-specific signals output from the multiplexer to perform an illumination function; And At least one visible light emitting diode (LED) for converting an electrical signal into an optical signal in the visible light region and transmitting the visible light emitting diode unit for transmitting visible light corresponding to the signal output from the signal selector to the outside Inter-vehicle communication device comprising a. The method of claim 1, The visible light receiving unit, A photo-detector for receiving visible light from the outside and outputting it as a corresponding electric signal; A reception filter unit which removes and outputs a carrier component with respect to a specific frequency band component with respect to the electrical signal output from the photo detector; An equalizer for correcting and outputting a signal output from the reception filter unit; A demultiplexer configured to demultiplex the signals output from the equalizer by the number of users; And A demodulator for demodulating each of a plurality of user signals output from the demultiplexer and outputting the received data for each user to the communication processor; Inter-vehicle communication device comprising a. The method according to any one of claims 1 to 3, The communication processing unit, A transmission / reception processor configured to perform visible light communication between the upper processor and the outside through the visible light transmitter and the visible light receiver; A failure determination unit determining whether a case in which visible light communication is interrupted due to a failure while performing visible light communication with the outside based on the communication data through the transmission / reception processing unit; When the visible light communication with the outside is interrupted due to the failure by the failure determination unit, a search unit for searching whether there is a street light that can be visible light communication with the vehicle of the external street lamps around the vehicle; And The visible light communication with the other vehicle is controlled by controlling the transmission / reception processing unit, the failure determining unit and the search unit, and the visible light communication with the other vehicle is determined to be stopped by the failure determining unit, and the visible light communication is performed by the searching unit. If a possible street light is found, a communication control unit performing visible light communication with the found street light. Inter-vehicle communication device comprising a. The method of claim 4, wherein The street light is an inter-vehicle communication device, characterized in that for performing visible light communication, wireless communication or optical communication with the surrounding street light. In an inter-vehicle communication method in which an on-vehicle communication device mounted on a vehicle transmits and receives data through visible light communication with another vehicle, Performing visible light communication with another vehicle; Determining whether visible light communication with the other vehicle is stopped; And If the visible light communication is interrupted, communicating with the other vehicle through a street lamp around the vehicle; Inter-vehicle communication method comprising a. The method of claim 6, Performing communication with the other vehicle, If it is determined that visible light communication with the other vehicle is stopped, searching for a street light capable of visible light communication around the vehicle; And Performing a visible light communication with the found street light when a street light capable of visible light communication is found around the vehicle; Inter-vehicle communication method comprising a. The method of claim 6, The street light is a vehicle-to-vehicle communication method characterized in that performing visible light communication, wireless communication or optical communication with the surrounding street light. A plurality of vehicles each equipped with an inter-vehicle communication device configured to transmit and receive data through visible light communication; And A roadside mesh network in which multiple streetlights capable of visible, wireless or optical communication form a mesh network node with each other. Including; When the visible light communication between the plurality of vehicles becomes impossible, the plurality of vehicles continue to communicate with each other through a street lamp, which is a mesh network node of the roadside mesh network. Intelligent communication system, characterized in that. The method of claim 9, The inter-vehicle communication device, A visible light transmitter for transmitting data to the outside through visible light communication; Visible light receiving unit for receiving data from the outside through the visible light communication; And Receives the information data to be transmitted to the outside from the upper processing unit in the vehicle and transmits the data to the other vehicle through the visible light transmitting unit, and transmits the data received from the other vehicle through the visible light receiving unit to the upper processing unit, the visible light When the visible light communication performed through the transmitter and the visible light receiver becomes impossible due to a failure, a communication processor for controlling communication with the other vehicle through a street light of the roadside mesh network capable of visible light communication. Intelligent transportation system comprising a. The method of claim 10, The communication processing unit, A transmission / reception processor configured to perform visible light communication between the upper processor and the outside through the visible light transmitter and the visible light receiver; A failure determination unit determining whether a case in which visible light communication is interrupted due to a failure while performing visible light communication with the outside based on the communication data through the transmission / reception processing unit; When the visible light communication with the outside is interrupted due to the failure by the failure determination unit, a search unit for searching whether there is a street light that can be visible light communication with the vehicle of the external street lamps around the vehicle; And The visible light communication with the other vehicle is controlled by controlling the transmission / reception processing unit, the failure determining unit and the search unit, and the visible light communication with the other vehicle is determined to be stopped by the failure determining unit, and the visible light communication is performed by the searching unit. If a possible street light is found, a communication control unit performing visible light communication with the found street light. Intelligent communication system comprising a. The method according to claim 9, wherein And a plurality of street lights of the roadside mesh network form a communication network using multi-hops. The method of claim 12, When the plurality of vehicles are communicating through the street light of the roadside mesh network, when a communication failure occurs in the streetlight, the roadside mesh network forms a new path through other streetlights except for the streetlight so that the plurality of vehicles Intelligent transportation system, characterized in that the communication between.

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